High-performance hydrogen evolution of MoSe2-Mo2C seamless heterojunction enabled by efficient charge transfer

Transition metal dichalcogenides (TMDs), such as molybdenum diselenide (MoSe2) has poor alkaline hydrogen evolution activity due to its unfavorable hydrogen adsorption and dissociation property. In this work, we report a Mo2C/MoSe2 hybrid catalyst seamlessly grown on Mo foil. Mo2C/MoSe2/Mo electrode exhibits outstanding activity for hydrogen evolution reaction (HER) with a low overpotential 43 mV at 10 mA/cm2 in 1 M KOH, significantly outperforming the performance of MoSe2 and Mo2C counterparts and most of reported TMD electroncatalysts in alkaline solution. Moreover, Mo2C/MoSe2/Mo electrode also possess good catalytic HER performance in acid. Density functional theory (DFT) calculations reveal that metal-induced gap states formed in the interface region of Mo2C and MoSe2 can make the interfacial semiconducting MoSe2 transform into metallic MoSe2. The transformation is beneficial to speeding up the charge transfer between the interfaces, promoting H atom adsorption and desorption kinetics, therefore enhancing the catalytic performance.